When it comes to mobility, the story's much bigger than the iPhone. Enterprises are poised to expand their wireless investments considerably over the next 12 to 18 months, according to a just-published Nemertes Research benchmark, "Building the Successful Virtual Workplace."

The average growth rate of organizations (both large and small) looking to increase the number of devices they use over the next 12 months is 421%, according to the research. Companies are investing top dollar to enable employee mobility: Organizations with revenues of more than $1B report spending a median of $5,000 per year per mobile-enabled user. For PDA users, the median spend is $5,357; and for wireless laptop users, the median spend is $4,611.

The challenge to IT executives is how to handle the explosion of users and applications. "Crafting a mobility strategy is a key priority of benchmark participants, with 60% of enterprises indicating they currently have or are planning adoption of a mobility strategy," says Johna Till Johnson, Nemertes president.

Multi-mode and multi-function devices are another key for IT executives: 75% of benchmark participants say they're interested, or somewhat interested, in multimode products - devices that handle both WiFi and various flavors of wireless-WAN services.

The research benchmark includes recommendations and best practices for creating a mobility strategy, the return on investment of mobility, and the next big wireless and mobility trends, including WiMax. It also addresses the critical areas of security and application integration.